Finding the Fourth Proportional to 2,111.40, 2,907.90 and 1,917

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.40 : 2,907.90 = 1,917 : x
2. Step 2: Convert to fraction form
   2,111.40/2,907.90 = 1,917/x
3. Step 3: Cross multiply
   2,111.40x = 2,907.90 × 1,917
4. Step 4: Simplify right side
   2,111.40x = 5,574,444.30
5. Step 5: Solve for x
   x = 5,574,444.30/2,111.40
6. Step 6: Final answer
   x = 2,640.16